Such a method is known from EP1592008 where a method for mixing two digital data sets into a third digital data set is disclosed. In order to fit two digital data sets into a single digital data set with a size smaller than the sum of the sizes of the two digital data sets, a reduction of information in the two digital data sets is required. EP1592008 achieves this reduction in defining an interpolation at samples between a first set of predefined positions in the first digital data set and at a non-coinciding set of samples between predefined positions in the second digital data set. The value of the samples between the predefined positions of the digital data sets are set to the interpolation value. After performing this reduction in information in the two digital data sets, each sample of the first digital data set is summed with the corresponding sample of the second digital data set. This results in a third digital data set comprising the summed samples. This summation of samples together with known relationship of the offset between the predefined positions between the first digital data set and the second digital data set allows the recovery of the first digital data set and the second digital data set, albeit only with the interpolated samples between the predefined positions. When the method of EP1592008 is used for audio streams this interpolation is not noticeable and the third digital data set can be played as a mixed representation of the two digital data sets comprised. In order to enable the retrieval of the first and second digital data set with the interpolated samples, a start value for both the first and second digital data set must be know and hence these two values are also stored during mixing to allow a later unraveling of the two digital data sets from the third digital data set.
The method of EP1592008 has the disadvantage that it requires intensive processing on the encoding side.